Molding press



-L/i zm ik f7 l Jan. 6, 1942 M. F. WEIDA 2,269,389

MOLDING PRESS Y Filed March 4, 1958 s sheets-sheet 1 O mumllull'llmlf 12l Il" l www" MW f4 www l 2 l 45 Il 1 i# 5, 55- 32 20T 40 59 3, lgraue/Moz Fly] f './l/illdmhida l I MW Jan. 6, 1942 M. F. WEIDA4 MoLDINGPRESS I Filed March 4, 1938 5 Sheets-Sheet 2 -ulwwwfj -i W w s d 1 umJan. 6, 1942 M. F. wElDA 2,269,389

MOLDING PRES S Filed March 4, 1958 s sheet-sheet s Patented Jan.. 6,1942 UNITED STA-'111515 PATENT l 0F F I CE* 2,2695@ f MOLDING PllsMillardF. Weida, near Louyisyille, Ohio l Appiiatipn March 4, issaserialisp. 179:3.,95-

v9 Claims.

The invention relates to presses forv molding plastics such as rubber,Bakelite and the like, and the object of the present invention is toprovide a press of this character with meansfor rapidly bringing themold sections nearly to closed .posil tion under low pressure and thenmore slowly closing the moldsy under high pressure.

Another object is to provide a press of the type referred to arranged tobe operated by fluid cyl-'- inders with means for holding the moldsections in closed position under high pressure so that the fluidcylinders may be released when the mold` sections are closed.

A further object is to provide a molding press in which the moldsections are arranged to `be clcsedby toggle levers, two fluid cylindersbeing arranged to successively operate to move the' levers to the closedposition.

A still further object of the improvement is lto provide means wherebythe secondr or high pressure cylinder will be automatically operatedwhen the toggle'levers reach a predetermined position.

Still another object is to provide means forautomatically controllingthe operation of the cylinders so as to move the parts throughacompletecycle each time the press is started.

The above objects together with others which will be apparent from thedrawings and followthe upper ends vof the guide rods as by the nutsyI3'loc`ated ponthe threaded upper' ends I4 of the rods, Washers I5 oflany desired thickness being interposedbetween ther cross-head and theiixedcollars or shoulders I6 of the rods.

' The upper vor fixed mold section is adapted to l be attached to thecross-head I2 as by the T-grove I8. "The lower'mold sectionV is adaptedtobe attached in` the same mannerto thel block l 9 which is slidablymounted upon the guide rods I Ian'd'provided with the T-grooves 20.

- iflpair oftogglelevers 2 I land 22 is provided for raising andlowering the block I 9 upon the guide rods, the upper lever 2 I beingpivotally connected ing description or which may be later referred to,

may be attained by constructing the improved molding press inthe mannerlillustrated in the accompanying drawings in which:

Figure lis a side elevation, partly in section of a molding pressconstructed in accordance kwith the invention, showing the parts in theopen or s initialposition; v

Fig. 2, a fragmentary sectional elevation similar to Fig. 1 showing thepartsA in the vclosed or operated position; f'

Fig. 3, a transverse sectional elevation of the press taken on the line-3-3 Fig. 1;

Fig. 4, a detached, perspective View of the bifurcatedhead which'forms aconnection'between the toggle levers and the second fluid cylinder; and

Fig. 5, a diagrammatical view showing the cylinders, valves and electricwiring forV operating the press.

Similar numerals refer to 'similar throughout the drawings.

The base of the press is in theform of a housparts ing I0 within whichis enclosed the operatingl mechanism. i Four spaced upright guiderodsfll are secured at their lower ends to the housing I0 and a`cross-head I2 is adjustably,mountedupon tothe sliding block as by pin23 located through the upperendo'f'the lever and `through the dependinglugs 24 formed upon the block.

The '.togglelevers' v'2-I and ,22 are pivotally connected-together as bythe pin 25 and the lower lever 22 is fixedV upon a shaft 26 journaled inbearings .2l.located within the housing I0 and preferably suspended,from the cover plate 28 thereof as by the Webs 29. l

Thelever 2| maybe adjustable in length as by means of vthe'oppositelythreaded screw. 30 locatedat.itsintermediateportion and received in .thesplit4 internally threaded sockets 3I providedWithllam'pi'ng'screws321for holding any desired adjustment, a squared orhexagonal head 33 being formed atthe central portion of the Oppositelythreaded screw to`receive a wrench orLthe like for @adjusting rthe same.This adjustment provdesfor. the use `of mold sections of varyingthicknesses.

- Apinion 34 is fixed upon the shaft 26and may be formed integrally withthe .lever 22 vas best shown injFigs. 1 and 2. 'I'his pinion meshes witharack bar35, slidable within a guidewayn36 which may be. formed integralwiththe bearings 2l and supported by the webs 29. l

Afluid operated low pressure cylinder. 3l is mounted within the bottomofthe housing I0 and .the piston rody 38. thereof is fixed to the rack bar35 solthatithe rack bar is reciprocated within its guide whenthecylinder isoperated.

Ahighlpressure fluid operated cylinder 39 is locatedV in the upperportion of the housing and thel piston.. rod,40 thereof has the yokev 4Ifixed to its outer end. This yoke is arranged to straddley the togglerlevers and/fis mounted to slide within guides I2A formed in the coverplate28 of thehousing. n

The lever 22 has an oir-set portion 43 at its o uter end through whichis located a pin 44 extending outward .toeach side of thev lever and 2adapted to be received in the notches 45 of the yoke 4| as will be laterdescribed.

In order to automatically operate the press through a complete cycleeach time the same is started, a series of valves and switches asdiagrammatically shown in Fig. 5 may be provided for operating the lowand high pressure cylinders at the proper times.

The cylinders are adapted to be operated by means of a pump 46 connectedwith a reservoir or tank 41 and with a four-way valve 48 arranged toselectively admit uid under pressure to either end of each of thecylinders 31 and 39.

The pump 46 may be driven by an electric motor 49 which is adapted to beoperated through a reversing switch indicated generally at 50 by meansof the three-phase circuit comprising the wires 5l, 52 and 53 leadingfrom any suitable source of electric energy. I

The four-way valve 48 is connected by a pipe 54 with the tank 41 and isalso connected by a pipe 55 with the three-way valve 56. A pipe 51 leadsfrom the four-way valve to the forward end of the low pressure cylinder31, and a pipe 58 communicating therewith and having the speed controldevice 59 located therein leads to the three-way valve 56 which isconnected as by the pipe 60 with the rear end of the high pressurecylinder 39.

A pipe 6| leads from the four-way valve 48 to the forward end of thehigh pressure cylinder 39 and communicates with the pipe 62 which leadsto the rear end of the low pressure cylinder 31.

The three-way valve 56 is arranged to be operated by a pilot valveindicated generally at 63 and connected by a pipe 64 with the pump 46.

Pipes 65 and 66 are arranged to provide communication between the pilotvalve 63 and opposite ends of the three-way valve 56 so that oilpressure from the pump through the pipe 64 may be conveyed through thepilot valve 63 to either end of the three-way valve 56 in order to seatthe same in either operative position.

A hand operated lever 61 is provided for throwing the four-way valve 48to either position and is operatively connected to a pair of double poleswitches indicated generally at 68 and 69 and adapted to be operated bya solenoid 10.

The reversing switch indicated generally at 50 comprises two multipleblade switches 1| and 12 for operating the motor 49 forward and inreverse respectively, these switches being arranged to be operated bythe magnets 13 and 14 respectively.

Line wires 5|, 52 and 53 are connected to the contact points 15, 16 and11 respectively of the forward side of the switch and the correspondingcontact points 18, 19 and 80 respectively are connected as by the wires8|, 82 and 83 to the motor 49, the switch blades 84, 85 and 86respectively being adapted for closing the circuit from the line wiresthrough these wires to the motor to operate the same forwardly.

. 'I'he line wires are similarly connected'to the contact points 81, 88and 89 of the reversing side of the switch and the corresponding contactpoints 90, 9| and 92 are connected by the wires 93, 94 and 95respectively to the motorA 49, and the blades 96, 91 and 98 respectivelybeing adapted to close the circuit from the line wires to the motor tooperate the same in reverse.

The solenoid operated switch 68 has two blades 99 and 99a, the blade 99closing a circuit through the magnet 13, normally closed plunger switch|0| and switch blade |06 of the starting switch. The normally openplunger switch |02 controls a circuit through the magnet 14 on thereversing side of the reversing switch 50.

A timer |03 is provided in the circuit for controlling the period duringwhich the mold sections remain closed in each cycle of operation of thepress. A magnet operated switch |04 is adapted to be operated by thetimer.

To start the automatic operation of the press, the switch blade |00 onthe push-button station is thrown to the auto position. The startingswitch |05 is closed and the lever 61 of the fourway valve 48 is thrownto the forward position.

'The circuit to the motor 49 is closed through the forward side of thereversing switch 50 by the closing of the one set of contacts throughthe blade 99 of the double pole switch 68 which energi'zes the magnet 13closing the multiple blade switch on the forward side of the reversingswitch 50. Through the other blade 99a. of the switch 68 the circuit isclosed through the timer |03.

The four-way valve 48 has thus been operated by moving the lever 61forward to admit fluid to the forward end of the low pressure cylinder31 driving the piston rod 38 thereof inward and reciprocating the rackbar 35 in the direction of the arrows shown in Figs. 1 and 5 operatingthe toggle levers 2| and 22 rapidly to raise the sliding block I9 almostto the position where the die sections are closed.

As the toggle levers reach a position where the pins-44 on the lever 22are received into the notches 45 in the sliding yoke 4| further movementof the toggle levers in this direction will slide the yoke 4| a slightdistance in the direction of the arrow shown in Fig. 5.

The finger |06 upon the yoke operates the pilot valve 63 to admit oilunder pressure to the threeway valve 56 to set said valve in position toadmit fluid to the rear end of the high pressure cylinder 39 whichcontinues the movement of the yoke 4| in the direction of the arrowslowly closing the mold sections under high pressure and throw- 4 ingthe pivot 25 of the toggle levers over center at which time the plungerswitch |0| is opened by contact with the yoke 4|.

It will be seen that the plunger switch |02 will close as soon as theVtoggle levers first start to operate. The opening of the plunger switch|0| breaks the circuit to the motor, stopping the same and holding thedies closed Without operation of the fluid pressure cylinders.

At the end of the set time-the timer will operate to energize the magnet|08 closing the switch |04 which in turn energizes the solenoid 10 whichpulls the valve lever 61 to the reverse position breaking Contact of theblade '|09 of the switch 69 and closing contact by the blade ||0 of saidswitch, pulling the reversingY switch to the reversed position, startingthe motor in reverse, and stopping and resetting the timer. The valvesare thus operated to reverse the flow of fluid through the cylinders 31and 39 to bring the toggle levers 2| and 22 back to the initial positionand as they reach this position they will automtically open the plungerswitch |02 stopping the motor.

The machine Will now remain idle until the oil valve lever 61 is againmoved to the forward position starting another cycle of operation.

Although the arrangement of valves, pipes and electric wiring andswitches diagrammatically shown in Fig. 5 has been found in practice tobe very satisfactory for automatic operation for the improved moldingpress, it is pointed out that e acca-'seo there may be many-otherarrangements of valves and wiringY by means of which th'epr'e'ss may beoperated but this one arrangement is 'shown to illustratev completelythe operation of the press which in itself forms the subject matter ofthe present invention rather than any particular electrical or fluidcontrol means. t

I claim:

l. iA molding press including a stationary mold section, va movable moldsection, a pair of 4toggle levers pivotally connected together, onelever being pivotallyconnected to said movable 4mold sec'- tion, arotatable shaft'uponwhich'the other lever is Xed, a fluid cylinder for.rotating said lshaft to move `the toggle levers until the mold.sections are nearly closed, a second 'cylinder having a piston rod, avalve forv controlling theadmission of fluid .to the second fluidcylinder, pin and shoulder means upon rsaid 'piston rod and upon oneofsaid levers adjacent to the pivotal joint of said levers, positioned tobe interengaged upon movement of said toggle levers to close the moldsections, said shoulder being `moved by said pin while being so:interengaged and means on said piston rod and movable by said shoulderfor opening said valve to admit fluid .to the second fluid cylinder whenthe pin engages and moves the shoulder whereby the last named piston rodwill further move the toggle levers in order to fully close the moldsections.

2. A molding press including a stationary mold section, a movable moldsection, a pair of toggle levers pivotally connected together, one leverbeing pivotally connected to said movable mold section, a rotatableshaft upon which the other lever is fixed, a fluid cylinder for rotatingsaid shaft to move the toggle levers until the mold sections are nearlyclosed, a second fluid cylinder having a piston rod, a valve forcontrolling the admission of fluid to the second fluid cylinder, and pinand shoulder means upon said piston rod and upon one of said leversadjacent to the pivotal joint of said levers positioned to beinterengaged upon movement of said toggle levers to close the moldsections, said shoulderbeing moved by said pin While being sointerengaged and means on said piston rod and movable by said shoulderfor opening said valve to admit fluid to the second fluid cylinder whenthe toggle levers reach a predetermined position and when the pinengages and moves the shoulder whereby the' second fluid cylinder willfurther move the toggle levers in order to fully close the moldsections.

3. A molding press including a stationary mold section, a movable moldsection, a pair of toggle levers pivotally connected together, one leverbeing pivotally connected to said movable mold section, a rotatableshaft upon which thev other lever is fixed, a fluid cylinder forrotating said shaft to move the toggle levers until the mold sectionsare nearly closed, a pin upon one of the levers, a second fluid cylinderhaving a piston rod' provided with a shoulder positioned to be engagedby said pin and to be moved thereby upon movement of said levers toclose the mold sections, a valve for controlling the admission of fluidto said second fluid cylinder and means upon the piston rod of thesecond fluid cylinder for operating the valve when the pin engages theshoulder upon the piston rod and moves the piston rod whereby the pistonrod will further move said toggle levers in order to fully close themold sections.

4. A molding press including a stationary mold section, a movable moldsection, a pair of toggle levers pivotally connected together, one leverberod provided with a shoulder positioned to be engaged by said pin andbe moved thereby upon movement of said lcvers-to close the moldsections, a valve for controlling the admission of fluid to said secondfluid cylinderl and means upon the piston rod of the second fluidcylinder for operating the valve when the pin engages the shoulder uponthe piston rod and moves the piston rod whereby the piston rod willfurther move said toggle levers over center in order to fully close themold sections and hold them inclosed position, and means for thenstopping the operation of the fluid cylinders.

5. A molding press including a static-nary mold section, a movable moldsection, a pair of toggle levers pivotally connectedtogether, one leverbeing pivotally connected to said movable mold section, a rotatableshaft upon which the other lever is fixed, a fluid cylinder for rotatingsaid shaft to move the toggle -levers until the mold sections are nearlyclosed, a pin upon one of the levers,

a second fluid cylinder having a piston rod provided with a notchpositioned to be engaged by said pin and be moved thereby upon movementof said levers t0 close the mold sections, a valve for controllingadmission'of fluid to said second cylinder and means upon the piston rodof the second fluid cylinder for operating the valve when the pinengages said notch and moves said piston rod whereby the piston rod willfurther move said toggle levers in order to fully close the moldsections.

6. A molding press including a stationary mold section, a movable moldsection, a pair of toggle levers pivotally connected together, one leverbeing pivotally connected to said movable mold section, a rotatableshaft upon which the other lever is fixed, a fluid cylinder for rotatingsaid shaft to move the toggle levers until the mold sections are nearlyclosed, a pin upon one of the levers, a second fluid cylinder having apiston rod provided with a notch positioned to be engaged by said pinand be moved thereby upon movement of said levers to close the moldsections, a valve for controlling the admission of fluid to said secondcylinder, means upon the piston rod of the second fluid cylinder foroperating the valve when the pin engages said notch and moves the pistonrod whereby the piston rod will further move said toggle levers overcenter in order to fully close the mold sections and hold them in closedposition, and means for then stopping the operation of the fluidcylinders.

7. A molding press including a stationary mold section, a movable moldsection below the stationary mold section, a pair of toggle leverspivotally connected together, the upper end of one lever being pivotallyconnected to the movable mold section, a rotatable shaft upon which thelower portion of the other lever is fixed, a fluid tioned to beinterengaged upon movement of said toggle levers to close the moldsections and means upon the piston rod of the second uid cylinder foropening the valve to admit fluid to the second fluid cylinder when thepin and shoulder means interengage and move said piston rod whereby thelast named piston rod will further move the toggle levers to fully closethe mold sections.

8. A molding press including a stationary mold section, a movable moldsection below the stationary mold section, a pair of toggle leverspivotally connected together, the upper end of one lever being pivotallyconnected to the movable mold section, a rotatable shaft upon which thelower portion of the other lever is fixed, a low pressure fluid cylinderoperatively connected to the last named lever below said shaft formoving the toggle levers until the mold sections are nearly closed, ahigh pressure fluid cylinder having a piston rod, a valve forcontrolling the admission of fluid to the high pressure fluid cylinderand pin and shoulder means upon said piston rod and upon one of saidlevers adjacent to the pivotal joint of said levers positioned to be`interengaged upon movement of said toggle levers to close the moldsections and means upon the piston rod of the high pressure fluidcylinder for opening the valve to admit iluid to the high pressure fluidcylinder when the pin and shoulder means interengage and move saidpiston rod whereby the last named piston rod will further move thetoggle levers to fully close the mold sections.

9. A molding press including a stationary mold section, a movable moldsection, a pair of toggle levers pivotally connected together, one leverbeing pivotally connected to said movable mold section, a rotatableshaft to which the other lever is fixed, a gear upon said shaft, a lowpressure fluid cylinder having a piston rod, a rack upon said piston rodengaging said gear for rotating said shaft to move the toggle leversuntil the mold sections are nearly closed, a pin upon one of the leversadjacent to the pivotal joint of the levers, a high pressure fluidcylinder having a piston rod provided with a shoulder positioned to beengaged and moved by said pin, a valve for operating the high pressurefluid cylinder, and means upon the piston rod of the high pressurecylinder `for opening the valve and starting the high pressure fluidcylinder when the pin engages and moves said shoulder whereby the lastnamed piston rod will further move the toggle levers in order to fullyclose the mold sections.

MILLARD F. WEIDA.

